L series race engine questions

[GreaseMonky]

So i have been doing alot of research and decided that I need to ask a few questions about my upcoming L series build

 

What I want to know is I need to build a race engine for my 510, It needs to be able to rev high and make power high, not worried about down low, has to have a l series head, and apear to be stock block, everything inside and be changed, also I have to run only 1 carb, but can be any 2 barrel, so like up to a holley 500

[datsunaholic]

So, the question was... ?

 

For high revs the L16 or L18 is a better choice, though overall HP will be less.

[mike]

If you dont need the displacement of an LZ22, look for a Z20 out of an early eighties 200sx. Its a rev happy sumbitch, its got longer rods than the L20 and all the L stuff bolts on. You might be able to run the Z20 rotating assembly with some Z/KA 24 pistons in a Z22 block and get a high revving big bore L, Im sure someone here knows for sure. If you can use a later block, look at building an LZ24... doesnt rev as high but its a good combo for a little extra grunt, it takes a little extra fabrication too.

 

Have you checked the Jason Grey info? I think its buried somewhere in the Ratsun FAQ... Theres a lot of good info in there for L series interchange/compatibility.

 

Keep us updated on what you do, Im going to watch this thread and Im curious to see what the pros have to say :cool:

[GreaseMonky]

I did check the Jason Grey Info, but there are so many different combos, I need to get the best combo for displacment, and revs, I dont think I wanna go teh LZ24 route, right now the Lsereis in my 610, hits 6900, just as I am coming into the corners on teh small track, the 510, is gonna be ran on a bigger track, about twice as big, I have a few different rear end gear options, so I can play with that, but I need more power then the 610 has

 

 

 

and the question is what are some of your guys opinions, like heads to get, I can run race fuel, and dont mind running it, so im not worried about alot of compression

[Dime Dave]

GreaseMonkey,

Where you are now racing, you know speed cost money.

 

The secret to power in any race engine is displacement. If you have no limits and the tech man isn't particular that the block is 1.5" taller than stock and the timing chain cover has been spliced together, build an LZ24-25. Otherwise go with an LZ22-23 from a Z22 block.

 

Next get a full on ported and polished race head. Start with a V912 core and have it professionally ported and polished. And run as much compression as the fuel you can get will allow. With a large displacement LZ engine and the small combustion chamber of the V912 head it will not take much dome size to be in the 14-15 to one range.

 

For a cam, contact Dave Generous at Cam Techniques in Florida. He has ground cams for Datsun circle track engines for years. He has a grind I have used that works good at hill climbs and tight road courses (#280-04 if memory is correct) 290 duration with .600" + lift. It will make good mid and upper end power to about 7500. Good for coming off the turns.

 

Use the Holley 350, it should be plenty big enough. Try and find an old Edelbrock single plane intake.

 

Run a 4-1 header with 34"-36" tube lengths, 1 5/8" diameter primary, 2.25"-2.5" collector. This will help with midrange power.

 

Try not to build all the power at the top end. Circle track racing uses a much broader power band than road racing. A typical circle track engine will need a 3K range of power, roadracers usually use a 1.5-2K rpm range of operation. The big carbs and long duration cams typically sold for L series race engines are for road racing and do not work the best at a circle track.

 

Hope this helps.

[GreaseMonky]

I think they may not like the LZ24 idea, thats why I was staying away from it, the block is suppose to be stock for make and model, but not year, and porting is not allowed so i am stuck trying to find a large port head

[Jesse C.]

L18 with an A87 or 219 head. L-20B if you want more grunt. You can run Z pistons and a your choice of cams or what ever your class limits you to. Just make sure the valvetrain is in good shape. The 350CFM carb would be ideal or a 38/38 Weber. 500CFM is way too much. Full length headers are also very necessary.

 

LZ combos are work and you have to make some custom stuff, like making the chain longer and modifying the timing cover.

 

If running a class, study your rulebook and proceed accordingly

[GreaseMonky]

Thanks for the info, I am trying to source some parts now

[GreaseMonky]

So I sourced a good Z22 block, so I guess the building will comence soon

[Dirttrack510]

I race with an L16 and run an WEBER 40 DFAV-1 carb. I constantly rev it to about 7 grand and the engine is nearly stock. If you build an L16 all the racing parts are readily available and will be much cheaper than building the L20. You can buy racing H beam rods for under $600 brand new if you do a little searching and Wisco can still make forged pistons for it in just about any overbore. If you call ISKY racing cams, you can talk to Ron and he will custom grind you a racing cam for your exact needs for around $120, you'll just need to send him a good used camshaft to regrind. He'll also sell you the correct springs, retainers, and lash pads, so you won't have to do any guess work. You can have Z style intake and exhaust valves installed in your head and do a full port and polish, along with a 4 or 5 angle valve job and easily get between 150 and 175 horsepower. I personally like the L16 for racing, because if properly balanced and assembled you can rev it to nearly 9 grand.

 

Also, I run 4.88 gears in my race wagon and it has made a BIG IMPROVEMENT in my exit speeds, coming out of the corners. If you look around, you should be able to find a center section with 4.60 gears that will bolt right into a sedan. I hope this helps, good luck with your racing program.

[troyt]

<<the block is suppose to be stock for make and model, but not year,>>

 

<<So I sourced a good Z22 block,>>

 

OK, so do you have an answer for Tech when they ask what year 510 came with a Z22 motor?? You could build a cheater L20 with a Z22 crank...

If you want to stay legal, the L20b did come in a 510. The stock counterbalanced crank works great (remove some weight from it if you desire), race prepped OE rods or aftermarket rods are readily available, and custom forged pistons at whatever CR you want are just a phone call away. If your lucky, find a V912 closed chamber head (about 41cc), and 44mm intake valves and 38mm exhaust valves are available from SI. If you can't find a V912, get a closed chamber A87 (A87's also come in open chamber) and have it well ported to make a poor man's V912. 12:1 CR works fine with available head gaskets, CRs in the 13-15:1 range will require some special sealing, ie MLS or o-rings. And as properly suggested, find a cam grind for roundy-round cars, but the Isky L4 cam with about 280 duration and .580 lift might be a great a cam for your purposes. Just my $.02 worth...

[datzenmike]

If you want to stay legal, the L20b did come in a 510.

 

I don't think the techs will see it that way. The '68-'73 PL510 only came with an L16 motor. It was the much later '78-'81 HL510 (A-10) that had the L20B motor. The HL510 is a 510 in name only and 5 years newer than the original 510.

 

You could easily mill the L20B that's stamped on the block and re-stamp it L16. Unless the techs notice that the top front of the timing chain cover has two bolts per side instead of one or they can tell by eye that the motor is 3/4" taller you could run an L20B and mod the hell out of it. Z22 crank and pistons can't be seen.

[datsunaholic]

The tech folks might, if all they look at is "Datsun 510". They don't care that it's an HLA10 vs PL510... the model is still a 510.

 

However, a Z22 block is going to present issues, as it wasn't used in the 510 ever. And using parts of a Z22 is also a big no-no. I don't know how bad they get in any racing that still uses 510s, but I know in the boat racing community you win a race, the head comes off and they measure bore and stroke. If you are over the allowed displacement for the class, you're DQ'ed. Pain in teh rear with an OHC engine, but you get used to it if you do well enough to get teched.

[GreaseMonky]

<<the block is suppose to be stock for make and model, but not year,>>

 

<<So I sourced a good Z22 block,>>

 

OK, so do you have an answer for Tech when they ask what year 510 came with a Z22 motor?? You could build a cheater L20 with a Z22 crank...

If you want to stay legal, the L20b did come in a 510. The stock counterbalanced crank works great (remove some weight from it if you desire), race prepped OE rods or aftermarket rods are readily available, and custom forged pistons at whatever CR you want are just a phone call away. If your lucky, find a V912 closed chamber head (about 41cc), and 44mm intake valves and 38mm exhaust valves are available from SI. If you can't find a V912, get a closed chamber A87 (A87's also come in open chamber) and have it well ported to make a poor man's V912. 12:1 CR works fine with available head gaskets, CRs in the 13-15:1 range will require some special sealing, ie MLS or o-rings. And as properly suggested, find a cam grind for roundy-round cars, but the Isky L4 cam with about 280 duration and .580 lift might be a great a cam for your purposes. Just my $.02 worth...

 

The way the economy is they dont make us tear down anymore, and the when they do it is only pulling the intake and exhaust mani, to check for porting, they dont car about valve size, and there is no bore limit, we can run any displacment as long as its a 4 cylinder, and its the stock block for make and model, for some reason I though that the later 510 came with a NapsZ engine, guess i should research more

[datzenmike]

Late '78 and all of '79 were L20B. '80 and '81 were NAPS Z20E in the US. In Canada the L20B was continued through '80 and then switched to the Z20E.

[troyt]

So GreaseMonkey, it all comes down to the rules of your race organization, and how specific their "make and model" specification is. If all they require is a four cylinder, then your options are almost limitless. If that is the case, you could also go twin cam, cross-flow, etc. Some guys in the southern US who race dirttracks all switched from L motors to K motors in their 510s when their engine rules were changed. My vintage race group requires L motors, basically L16 in C Sedan, L18 in B Sedan, and L20 in GTL. If your rules are loose enough but still require an "original style engine", heck, build a bad ass NAPS Z24, no replacement for displacement in racing, revs are just a matter of race prep. I have a friend who is racing a Rebello L/Z24 that must make over 250 at the wheels and runs with the V8s ;-)

[GreaseMonky]

They leave a very large grey area but i dint think i can get away with putting a KA in here is a copy of the rules

 

http://river-city-speedway.com/4-Cylinder_Rules_2012_1_.pdf

[datsunaholic]

The rules state that the transmission must match the year, make, and model with no modifications. That severely limits things even if the engine doesn't have to match year, since the transmission would have to be stock. The stock F4W63 can't take much over 110HP, and per the rules you can't go putting a Z-car trans in there.

 

Note that the late 510 (A10) did come with a NAPS-Z engine, but ONLY the Z20S.

[GreaseMonky]

and thats the thing, thats so frustrating, is alot of guys, especially in the older cars, change the trans out to later years, becuase of the lack of being able to source parts. And the tech never looks, for example I raced the winter series in my 610, and ran a 2" adapter for my weber and the rule says 1" max, and no one cared, and on my 510 I am buliding, im running adjustable LCA, and i argued that there are stock LCA, mounted in stock location, which is what the rules say, and the allowed it, along with my rear crossmeber being adjustable, and they allowed that, the even allowed my front coil overs, and my rear weight jacks, they said I had to tac weld them so I cant adjust them at the track. we only run second gear, so I am ok with running a 4 speed, and we dont slam the clutch or bang any gears like if we where drag racing

[GreaseMonky]

and what they explained to me, is they dont want people putting circle track racing tranny in, or taken some of the gear clusters out,

[datsunaholic]

Well, I was just going by what the rules say. Happens in every racing series. I'm more involved in boat racing and they're REALLY strict with the engine rules. There's only a few classes that Datsun engines are legal in anyway (and none are stock classes).

[datzenmike]

The 80-81 HL510 ran a look alike 510 4 speed. It has the distinctive removable bottom pan and no one is going to look to see that it actually has a Z and KA tilt to the bolt pattern. This would allow a KA24E or DE to bolt up, L20B 200mm flywheel, roadster clutch.

[GreaseMonky]

The 80-81 HL510 ran a look alike 510 4 speed. It has the distinctive removable bottom pan and no one is going to look to see that it actually has a Z and KA tilt to the bolt pattern. This would allow a KA24E or DE to bolt up, L20B 200mm flywheel, roadster clutch.

 

Ok this question is for a different engine that I am already running. I put i different cam in the L20 thats in my 610 last winter, and I was wondering, when i put the cam in I used the #2 position on the cam sprocket, can I move it to #3 position to gain more topend?? and if so, can I do it with out pulling the timing cover?

[Sealik]

Ok this question is for a different engine that I am already running. I put i different cam in the L20 thats in my 610 last winter, and I was wondering, when i put the cam in I used the #2 position on the cam sprocket, can I move it to #3 position to gain more topend?? and if so, can I do it with out pulling the timing cover?

 

Position # 3 will give you a little better bottom end.

Position # 1 ........................................ top end.

Yes it can be changed without removing TC cover.

Set engine at TDC...wedge chain...mark the chain at the No 2 sprocket position.

Remove sprocket....line up that mark on the chain to the new position (1 or 3) on sprocket

You might have to rotate the cam a bit to re-install it....depends how tight/new the chain is.

 

Moved mine to No 3.

 

[GreaseMonky]

Position # 3 will give you a little better bottom end.

Position # 1 ........................................ top end.

Yes it can be changed without removing TC cover.

Set engine at TDC...wedge chain...mark the chain at the No 2 sprocket position.

Remove sprocket....line up that mark on the chain to the new position (1 or 3) on sprocket

You might have to rotate the cam a bit to re-install it....depends how tight/new the chain is.

 

Moved mine to No 3.

 

 

hmm, well i am not exactly sure which way i should go with the cam, its not stock, and I dirt track race this engine as well, and am running higher up in the rpm range